Cycling and bicycle discussion forums. 
   Click here to join our community Log in to access your Control Panel  


Go Back   > >

Folding Bikes Discuss the unique features and issues of folding bikes. Also a great place to learn what folding bike will work best for your needs.

User Tag List

Reply
 
Thread Tools Search this Thread
Old 03-03-14, 10:02 PM   #1
adlai
Senior Member
Thread Starter
 
Join Date: Jun 2009
Bikes:
Posts: 491
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
building a s3x into a folding bike

One idea that has intrigued me recently is the idea of putting a Sturmey Archer s3x into a folding bike like a Montague Boston. I'd actually probably use a flywheel with it since the goal would be versatility. The s3x looks like it's a bit more durable than other IGH hubs too.

Thinking about it, the only problem I can think of is that during folding, the cable tension to the hub in the rear wheel might be interrupted, which would ruin the hub setup. Of course, the Boston 8 exists, which uses an 8 speed internal hub. In my imagining of the bike, I'd use bullhorns which would fold down during transport...

So, is that a problem?
adlai is offline   Reply With Quote
Old 03-03-14, 10:26 PM   #2
downtube
Senior Member
 
downtube's Avatar
 
Join Date: Sep 2005
Bikes: Many Downtube Folders :)
Posts: 931
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
why not an SA 8sp? I think new IGH are very durable....and efficient.

Om,
Yan
__________________
Designer of Downtube Folding Bike
Ph.D. Temple University ( Math )
Biked across the USA twice
Semi-active chess player ( two time Bahamas National Champion )
Sivananda ( Bahamas ) Trained Yoga instructor ( 2013 ) and ThetaHealer since 2013
downtube is offline   Reply With Quote
Old 03-03-14, 10:45 PM   #3
fietsbob 
coprolite
 
fietsbob's Avatar
 
Join Date: Jun 2010
Location: NW,Oregon Coast
Bikes: 7
Posts: 18,086
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
S3X + Freewheel? why not an S-A 5 speed .. S3X is the bottom 3 ratios of the 5 speed anyhow.
fietsbob is offline   Reply With Quote
Old 03-04-14, 12:05 AM   #4
adlai
Senior Member
Thread Starter
 
Join Date: Jun 2009
Bikes:
Posts: 491
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by fietsbob View Post
S3X + Freewheel? why not an S-A 5 speed .. S3X is the bottom 3 ratios of the 5 speed anyhow.
relative simplicity and weight.
adlai is offline   Reply With Quote
Old 03-04-14, 12:26 AM   #5
fietsbob 
coprolite
 
fietsbob's Avatar
 
Join Date: Jun 2010
Location: NW,Oregon Coast
Bikes: 7
Posts: 18,086
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
You Got weight data to quote? the 3 planetary gears are there , just the inverse is not used.

3 speed s simpler the justification ?
AW3 has had a history going back to the 30's , and now is aluminum hub-shelled too ..

.. some in 28 spoke hub shells .. made for smaller wheels ..

Last edited by fietsbob; 03-08-14 at 01:37 PM.
fietsbob is offline   Reply With Quote
Old 03-04-14, 10:55 AM   #6
adlai
Senior Member
Thread Starter
 
Join Date: Jun 2009
Bikes:
Posts: 491
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
I've run small wheeled folding bikes before.

Didn't like them one bit. It just feels so unstable.

And yes, I've also run a SA8 before too. It didn't feel very efficient either.
adlai is offline   Reply With Quote
Old 03-04-14, 01:03 PM   #7
mconlonx 
Nobody
 
mconlonx's Avatar
 
Join Date: Jun 2007
Bikes:
Posts: 7,031
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 20 Post(s)
Quote:
Originally Posted by adlai View Post
One idea that has intrigued me recently is the idea of putting a Sturmey Archer s3x into a folding bike like a Montague Boston. I'd actually probably use a flywheel with it since the goal would be versatility. The s3x looks like it's a bit more durable than other IGH hubs too.

Thinking about it, the only problem I can think of is that during folding, the cable tension to the hub in the rear wheel might be interrupted, which would ruin the hub setup. Of course, the Boston 8 exists, which uses an 8 speed internal hub. In my imagining of the bike, I'd use bullhorns which would fold down during transport...

So, is that a problem?
If they don't have issues with the 8sp IGH version, why would you have issues with an S3X build, assuming you run housing similar to their stock 8sp model? You may run into issues if you get the single-speed frame and it doesn't have the integrated cable stops of the 8sp frame. But still, once the bike is assembled, cable tension should snap back to where it's supposed to be...

Do some research on the type of freewheel you need for the S3X as well -- I've only used them fixed, but I know there are specific brands or configurations of freewheel you need to make it work for this hub.
__________________
I know next to nothing. I am frequently wrong.
mconlonx is offline   Reply With Quote
Old 03-04-14, 01:19 PM   #8
fietsbob 
coprolite
 
fietsbob's Avatar
 
Join Date: Jun 2010
Location: NW,Oregon Coast
Bikes: 7
Posts: 18,086
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
some S3X equipped bikes have passed thru the LBS. the tips of the splines are threaded ..
fietsbob is offline   Reply With Quote
Old 03-04-14, 01:25 PM   #9
Rob_E
Senior Member
 
Rob_E's Avatar
 
Join Date: Jan 2008
Location: Raleigh, NC
Bikes: Surly World Troller, Dahon Boardwalk, Raleigh 20, and the frame of a Surly Longhaul Trucker
Posts: 1,916
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 4 Post(s)
Wouldn't it be easier/simpler/lighter to use the non-fixed SA 3 speed without the freewheel?

As far as cable tension goes, it's something you might have to keep an eye on, but it's easy to adjust and, as has been said, theoretically any changes to cable tension are undone when you unfold the bike, so just don't try and ride it when it's folded. Many folding bikes come with IGHs, so i must not present a huge issue. I had a bike that split in two, and this issue was solved by mounting the shifter to the seat tube, so the front half of the bike could be removed without messing with the shift assembly.

For simplicity, I have always been tempted to go with a two speed hub. There's one model that shifts automatically based on the speed you're traveling, and one that shifts with a brief back pedal. No shift lines required.

I have never done it, though, because I like more gears.
Rob_E is offline   Reply With Quote
Old 03-08-14, 07:31 AM   #10
bhkyte
Senior Member
 
bhkyte's Avatar
 
Join Date: Sep 2008
Location: York UK
Bikes: 2X dualdrive Mezzo folder,plus others
Posts: 2,779
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Personally I would go for dualdrive which would be compatable with brifters and be reliable.
bhkyte is offline   Reply With Quote
Old 03-08-14, 10:15 AM   #11
darukhan
Senior Member
 
darukhan's Avatar
 
Join Date: Nov 2011
Location: Chicago-land
Bikes:
Posts: 266
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
This is an interesting thread to me, because I've been considering removing my dual drive hub to replace it with an S3X hub on my Birdy bike.

Over the past year, I've found that I'm mostly changing between three gears during my commute, and that's using the internal gears, not the 8 speed cassette! Also, I've been intrigued with the idea of riding fixed, since I'm usually pedalling the entire route during my commute anyways. So I figure the best hub to try would be the S3X.

Adlai... the part that I really don't understand about this thread is why you are considering putting a freewheel on a fixed gear hub?

As Rob_E mentioned already, why not just get a different model S-A 3 speed internally geared hub that's NOT fixed?

Last edited by darukhan; 03-08-14 at 10:28 AM.
darukhan is offline   Reply With Quote
Old 03-08-14, 03:09 PM   #12
mconlonx 
Nobody
 
mconlonx's Avatar
 
Join Date: Jun 2007
Bikes:
Posts: 7,031
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 20 Post(s)
Quote:
Originally Posted by darukhan View Post
Adlai... the part that I really don't understand about this thread is why you are considering putting a freewheel on a fixed gear hub?

As Rob_E mentioned already, why not just get a different model S-A 3 speed internally geared hub that's NOT fixed?
S3X has a closer gear ratio and direct drive is at the top, not in the middle. How that figures into OP's decision to go that route, I don't know...

S3X
• Overall Range - 160%
• Gear 1 - 62.5% (-)37.5%
• Gear 2 - 75% (-)25% (Gear 1 + 20%)
• Gear 3 - 100% Direct Drive (Gear 2 + 33%)

AWC
• Overall Range - 177%
• Gear 1 - 75% (-)25%
• Gear 2 - 100% Direct Drive (Gear 1 + 33%)
• Gear 3 - 133% (+)33.3% (Gear 2 + 33%)
__________________
I know next to nothing. I am frequently wrong.
mconlonx is offline   Reply With Quote
Old 03-08-14, 03:16 PM   #13
darukhan
Senior Member
 
darukhan's Avatar
 
Join Date: Nov 2011
Location: Chicago-land
Bikes:
Posts: 266
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by mconlonx View Post
S3X has a closer gear ratio and direct drive is at the top, not in the middle. How that figures into OP's decision to go that route, I don't know...

S3X
• Overall Range - 160%
• Gear 1 - 62.5% (-)37.5%
• Gear 2 - 75% (-)25% (Gear 1 + 20%)
• Gear 3 - 100% Direct Drive (Gear 2 + 33%)

AWC
• Overall Range - 177%
• Gear 1 - 75% (-)25%
• Gear 2 - 100% Direct Drive (Gear 1 + 33%)
• Gear 3 - 133% (+)33.3% (Gear 2 + 33%)
Very good point about the gear range and direct drive placement.
darukhan is offline   Reply With Quote
Old 03-08-14, 03:21 PM   #14
fietsbob 
coprolite
 
fietsbob's Avatar
 
Join Date: Jun 2010
Location: NW,Oregon Coast
Bikes: 7
Posts: 18,086
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Sachs -Sram 3 speed is just a hair lower and higher than S-A.. for 1st and 3rd
.73 vs .75 and 1.36 vs 1.33
fietsbob is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -6. The time now is 04:24 AM.